HomeMy WebLinkAboutDrainage Reports - 12/20/2001 (4)1
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FINAL DRAINAGE AND EROSION
CONTROL STUDY
OAKRIDGE BUSINESS PARK,
THIRTY-FIFTH FILING
OAKRIDGE BUSINESS PARK PLAZA
Prepared for:
Rayno Seaser
344 E. Foothills Parkway, Suite 3-EB
Fort Collins, CO 80525
Prepared by:
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, Colorado 80550,
. (970) 686-6939
October 15, 2001
Job Number 137-01
North Star
Awww design, inc.
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October 15, 2001
Basil Harridan
City of Fort Collins Stormwater
700 Wood Street
Fort Collins, CO 80522-0580
RE: Final Drainage and Erosion Control Study for
' Oakridge Business Park, Thirty -Fifth Filing
Oakridge Business Park Plaza
Dear Basil,
I am pleased to submit for your review and approval, this Final Drainage and Erosion Control
' Study for Oakridge Business Park, Thirty -Fifth Filing. I certify that this report for the drainage
design of Oakridge Business Park, Thirty -Fifth Filing was prepared in accordance with the
' criteria in the City of Fort Collins Storm Drainage Manual.
I appreciate your time and consideration in reviewing this submittal. Please call if you have any
questions.
�r
Sincere
'
Patricia Kroetc
North Star Design,
ii
700 Automation Drive, Unit I Windsor, Colorado 80550
970-686-6939 Phone 970-686-1188 Fax
TABLE OF CONTENTS
TABLEOF CONTENTS...............................................................................................................
iii
1.
GENERAL LOCATION AND DESCRIPTION
'
1.1 Location...................................................................................................................1
1.2 Description of Property ............................................................................................1
'
2.
DRAINAGE BASINS AND SUB -BASINS
2.1 Major Basin Description..........................................................................................1
3.
2.2 Sub -Basin Description.............................................................................................1
DRAINAGE DESIGN CRITERIA
'
3.1 Regulations ........................ :......................................................................................
3.2 Development Criteria Reference and Constraints...................................................2
2
3.3 Hydrologic Criteria..................................................................................................2
.
'
3.4 Hydraulic Criteria...........................................:........................................:...............3
4.
DRAINAGE FACILITY DESIGN
4.1 General Concept......................................................................................................3
4.2 Specific Flow Routing.............................................................................................3
4.3 Drainage Summary ........................:.........................................................................4
5.
EROSION CONTROL
5.1 General Concept.....................................................................................................4
5.2 Specific Details........................................................................................................5
6.
CONCLUSIONS
6.1 Compliance with Standards.....................................................................:..............5
6.2 Drainage Concept....................................................................................................5
7.
REFERENCES.............................:......................................................................................6
' APPENDICES
A Vicinity Map
B Hydrologic, Computations
C Hydraulic and Detention Calculations
D Erosion Control Calculations
E Excerpts from Previous Reports
F Figures and Tables
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GENERAL LOCATION AND DESCRIPTION
1.1 Location
The Oakridge Business Park Thirty Fifth Filing (Oakridge Business Park Plaza) site is
located in the Oakridge Business Park, P.U.D. This project is located in the Northwest
Quarter of Section 6, Township 7 North, Range 68 West of the Sixth Principal Meridian,
in the City of Fort Collins, Larimer County, Colorado. See the location map in Appendix
A.
The project is located on the north side of Oakridge Drive, between McMurray Drive and
Wheaton Drive. The project is bounded on the south by Oakridge Drive, on the east by
an existing cemetery and a proposed daycare, on the north by Harmony Road and on the
west by an undeveloped lot.
1.2 Description of Property
The entire project consists of approximately 2.8 acres of land. The land is currently
undeveloped and slopes to the southeast at approximately 1%. The site currently drains
into the existing Oakridge Drive on the south boundary and a small portion drains to
Harmony Drive on the north boundary.
The project will consist of two buildings and associated parking. Oakridge Drive along
the south boundary and Harmony Road along the north boundary are existing and will
not require any improvements.
DRAINAGE BASINS AND SUB -BASINS
2.1 Major Basin Description
The proposed development lies within the McClellands Drainage Basin.. More
specifically, the site is a portion of Basin 230 of the Oakridge Business Park Master
Drainage Plan, as prepared by RBD Inc., dated June 22, 1990 and updated April 1, 1996.
An excerpt of the drainage schematic is shown in Appendix F.
1 2.2 Sub -basin Description
' Per the Oakridge Master Drainage Plan, Basin 230 requires detention and will have a 10
year release rate of 0.20 cfs per acre and a 100 year release rate of 0.50 cfs per acre. This
' detention pond (SWMM pond 47) discharges into McMurray Drive east of this site. The
street and other drainage facilities eventually convey flows to the Regional Detention
' Pond #2 at the end of Keenland Drive.
Per the Master Drainage Plan, developed flows from Basin 230 should be detained on site
rand released into the street. The required detention was calculated utilizing the revised
IDF curves which were adopted in March 26, 1999. Detention is provided on site in the
southeast corner of the site and a portion of the parking lot.
Portions of the Oakridge Business Park Master Drainage Plan and the subsequent update
are included in appendix F.
1 3. DRAINAGE DESIGN CRITERIA
3.1 Regulations
This report was prepared to meet or exceed the "City of Fort Collins Storm Drainage
' Design Criteria Manual' specifications. Where applicable, the criteria established in the
"Urban Storm Drainage Criteria Manual" (UDFCD), 1984, developed by the Denver
' Regional Council of Governments, has been used.
' 3.2 Development Criteria Reference and Constraints
The runoff from this site has been routed to conform to previous calculations completed
' with the Master Drainage Plan for the Oakridge Business Park, P.U.D. by RBD
Engineering Consultants dated June 22, 1990 and updated April 1, 1996. Detention for
this site is provided on site as required in the above -mentioned report.
In the event that the outlet pipe for the Detention Pond becomes clogged, the pond will
overtop in the entrance drive and reach Oakridge Drive. The maximum overtopping
elevation for the Detention Pond is 4975.12 and all of the buildings have finished floors
above this elevation.
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' 3.3 Hydrologic Criteria
'
Runoff computations were prepared for the 10-year minor and 100-year major storm
frequency utilizing the rational method.
All hydrologic calculations associated with the basins are included in Appendix B of this
report. Standard Form 8 (SF-8) provides time of concentration calculations for all sub -
basins. Standard Form 9
(SF-9) provides a summary of the design flows for all Sub -
basins and Design Points associated with this site.
'
Detention required for this site is provided on site in the proposed detention pond in the
southeast corner of the site.
3.4 Hydraulic Criteria
All hydraulic calculations within this report have been prepared in accordance with the
'
City of Fort Collins Drainage Criteria and are also included in Appendix C of this report.
4. DRAINAGE FACILITY DESIGN
4.1 General Concept
' A majority of the runoff from this site will flow to the proposed detention pond in the
southeast corner of the site and be released at a controlled rate into the existing Oakridge
' Drive. A small portion of the site will drain to Oakridge Drive on the south side of the
site and a small portion of the site will drain north to Harmony Road.
' 4.2 Specific Flow Routing
' A summary of the drainage patterns within each basin is provided in the following
paragraphs.
Subbasin 1 contains the majority of the site including both buildings and parking lot
' between the buildings. Runoff from this basin flows southeast across the parking lot to a
curb opening and into the proposed detention pond.
Subbasin 0-1 contains a small portion of the site along the north boundary. Runoff will
flow along Harmony Road to the east as it has historically done. Due to the desire to
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the existing trees along Harmony Road and to provide berms to buffer the site, regrading
to bring this runoff back on site was not possible. The amount of flow being released is
very small and does not exceed 0.2 cfs in the 100 year storm event.
Subbasin 0-2 contains a small portion of the site along the southern boundary. Runoff
from this basin will flow south to Oakridge Drive. This basin includes a small portion of
' the entry (south of the high point) and a landscape strip adjacent to Oakridge Drive. This
flow will also be released undetained but does not exceed 0.4 cfs in the 100 year storm
event.
' Required detention for this site was calculated using the predetermined release rates
mentioned above (0.2 cfs per acre in the minor storm and 0.5 cfs per acre in the major
storm). Due to site constraints and the inability to contain all of the stormwater runoff,
' the calculated allowable release rate was then reduced by. the amount of runoff that is
released from Basin 0-2 into the street without detention. In the minor storm the
' calculated allowable release is 0.60 cfs (3.05 acres x.0.2cfs) minus the free release from
Basin 0-2 (0.10 cfs) which gives the release rate of 0.51 cfs. In the major storm the
' calculated allowable release is 1.53 cfs minus the free release from Basin 0-2 (0.25 cfs)
which gives the release rate of 1.28 cfs.
4.3 Drainage Summary
This site is providing detention as required by the Oakridge Master Drainage Plan. Small
portion of the site will be released undetained due to site constraints. Water quality
enhancement will also be provided in the proposed pond. Flows will be released into
Oakridge Drive at the predetermined rate of 0.2 cfs per acre in the minor storm and 0.5
' cfs per acre in the major storm. The drainage facilities located on this site will. be
maintained by the owners of the site.
5. EROSION CONTROL
5.1 General Concept
This site lies within the Moderate Rainfall and Wind Erodibility Zone per the City of Fort
Collins Zone Maps. The potential exists for silt movement from the site and into the
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existing storm system during construction. Potential also exists for tracking of mud onto
existing streets which could then wash into existing storm systems.
Per the City of Fort Collins Erosion Control Reference Manual for Construction Sites and
' related calculations in Appendix D, the erosion control performance standard for the
subject site is 79.4%. The erosion control plan gives a performance standard of 71.0%.
' The proposed plan does not meet the performance standard but the plan utilizes Best
Management Practices to limit the amount of sediment that will leave the site. The plan
is adequate to meet the intended purpose of erosion control. Additional measures will
' allow the plan to meet the performance standard but will not add to the practical
effectiveness of providing erosion protection.
The erosion control escrow amount is $4965.
5.2 Specific Details
To limit the amount of silt leaving the site, several erosion control measures shall be
implemented during construction. Silt fence shall be placed along the north and south
' boundaries and a vehicle tracking pad shall be installed at the entrance off Oakridge
Drive to control the mud being tracked onto the existing pavement. During overlot
' grading, disturbed areas are to be kept in a roughened condition and watered to reduce
wind erosion.
6. CONCLUSIONS
6.1 Compliance with Standards
'
All computations that have been completed within this report are in compliance with the
City Fort Collins Erosion Control Reference Manual for Construction
of Sites and the
Storm Drainage Design Criteria Manual.
6.2 Drainage Concept
The proposed drainage concepts presented in this report and on the construction plans
'
adequately provide for the transmission of developed on -site runoff to the proposed
detention in into
pond the southeast comer of the site and the existing Oakridge Drive.
The onsite drainage facilities (curb, pans and chases) will provide for the 10- year and the
'
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100- year developed flows to reach the proposed detention facility. The existing
downstream facilities have been sized to accommodate the detention release from this
site.
If, at the time of construction, groundwater is encountered, a Colorado Department of
Health Construction Dewatering Permit would be required.
7. REFERENCES
1. City of Fort Collins, "Storm Drainage Criteria Manual", (SDCM), dated March,
1986.
2. Urban Drainage and Flood Control District, "Urban Storm Drainage Criteria
Manual", Volumes 1 and 2, dated March, 1969, and Volume 3 dated September,
1992.
3. Final Report for Hydrologic Model Update for the Foothills Basin Master
Drainage Plan by Anderson Consulting, Inc. dated July 15, 1999.
51
No Text
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APPENDIX B
HYDROLOGIC COMPUTATIONS
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APPENDIX C
HYDRAULIC AND DETENTION CALCULATIONS
C
DETENTION POND SIZING BY FAA METHOD
' . Developed by
Civil Eng. Dept., U. of Colorado
Supported by Denver Metro Cities/Counties Pool Fund Study
Denver Urban Drainage and Flood Control District, Colorado
' PROJECT TITLE: Oakridge 35°h - 10 year
t**** DRAINAGE BASIN DESCRIPTION
BASIN ID NUMBER = 1
BASIN AREA (acre)= 2.84
RUNOFF COEF = 0.63
***** DESIGN RAINFALL STATISTICS
DESIGN RETURN PERIOD (YEARS) = 10.00
INTENSITY(IN/HR)-DURATION(MIN) TABLE IS GIVEN
DURATION 5 10 20 30 40 50 60 80 100 120 150 180
1
INTENSITY 4.9 3.8 2.7 2.2 1.8 1.6 1.4 1.2 1.0 0.9 0.8 0.8
***** POND OUTFLOW CHARACTERISTICS: MAXIMUM ALLOWABLE RELEASE RATE = .51 CFS
OUTFLOW ADJUSTMENT FACTOR = 1
' AVERAGE RELEASE RATE = .51 CFS
AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR.
COMPUTATION OF POND SIZE
-----------------------------------------------------
RAINFALL
RAINFALL
INFLOW
OUTFLOW
REQUIRED
DURATION
INTENSITY
VOLUME
VOLUME
STORAGE
MINUTE
INCH/HR
ACRE -FT
ACRE -FT
ACRE -FT
-----------------------------------------------------
0.00
0.00
0.00
0.00
0.00
5.00
4.87
0.06
0.00
0.06
10.00
3.78
0.09
0.01
0.09
15.00
3.26
0.12
0.01
0.11
'
20.00
2.74
0.14
0.01
0.12
25.00
2.47
0.15
0.02
0.14
30.00
2.21
0.16
0.02
0.14
35.00
2.02
0.18
0.02
0.15
'
40.00
1.83
0.18
0.03
0.15
45.00
1.71
0.19
0.03
0.16
'
50.00
55.00
1.58
1.49
0.20
0.20
0.04
0.04
0.16
0.17
60.00
1.40
0.21
0.04
0.17
65.00
1.35
0.22
0.05
0.17
70.00
1.29
0.22
0.05
0.18
'
75.00
1.23
0.23
0.05
0.18
80.00
1.18
0.23
0.06
0.18
85.00
1.13
0.24
0.06
0.18
'
90.00
1.09
0.24
0.06
0.18
95.00
1.04
0.24
0.07
0.18
100.00
.0.99
0.25
0.07
0.18
'
105.00
110.00
0.96
0.94
0.25
0.26
0.07
0.08
0.18
0.18
115.00
0.91
0.26
0.08
0.18
-----------------------------------------------------
THE REQUIRED
POND SIZE
_ .1795016
ACRE
-FT
THE RAINFALL DURATION FOR THE ABOVE POND STORAGE= 85 MINUTES
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DETENTION POND SIZING BY FAA METHOD
Developed by
Civil Eng. Dept., U. of Colorado
Supported by Denver Metro Cities/Counties Pool Fund Study
Denver Urban Drainage and Flood Control District, Colorado
PROJECT TITLE: Oakridge 35th 100 Year
**** DRAINAGE BASIN DESCRIPTION
BASIN ID NUMBER = 1.00
BASIN AREA (acre)= 2.84
RUNOFF COEF = 0.78
***** DESIGN RAINFALL STATISTICS
DESIGN RETURN PERIOD (YEARS) = 100.00
INTENSITY (IN/HR) -DURATION (MIN) TABLE IS GIVEN
DURATION 5 10 20 30 40 50 60 80 100 120 150 180
INTENSITY 9.9 7.7 5.6 4.5 3.7 3.2 2.9 2.4 2.1 1.8 1.4 1.2
***** POND OUTFLOW CHARACTERISTICS:
MAXIMUM ALLOWABLE RELEASE RATE = 1.28 CFS
OUTFLOW ADJUSTMENT FACTOR = 1
AVERAGE RELEASE RATE = 1.28 CFS
AVERAGE RELEASE RATE = MAXIMUM RELEASE RATE * ADJUSTMENT FACTOR.
***** COMPUTATION OF POND SIZE
-----------------------------------------------------
RAINFALL
RAINFALL
INFLOW
OUTFLOW
REQUIRED
DURATION
INTENSITY
VOLUME
VOLUME
STORAGE
MINUTE
INCH/HR
ACRE -FT
ACRE -FT.
ACRE -FT
-----------------------------------------------------
0.00
0.00
0.00
0.00
0.00
5.00
9.95
0.15
0.01
0.14
10.00
7.72
0.24
0.02
0.22
15.00
6.66
0.31
0.03
0.28
20.00
5.60
0.34
0.04
0.31
25.00
5.06
0.39
.0.04
0.35
30.00
4.52
0.42
0.05
0.36
35.00
4.13
0.44
0.06
0.38
40.00
3.74
0.46
0.07
0.39
45.00
3.49
0.48
0.08
0.40
50.00
3.23
0.50
0.09
0.41
55.00
3.05
0.52
0.10
0.42
60.00
2.86
0.53
0.11
0.42
65.00
2.74
0.55
0.11
0.43
70.00
2.62
0.56
0.12
0.44
75.00
2.50
0.58
0.13
0.44
80.00
2.38
0.59
0.14
0.44
85.00
2.31
0.60
0.15
0.45
90.00
2.23
0.62
0.16
0.46
I
95.00
2.16
0.63
0.17
0.46
100.00
2.08
0.64
0.18
0.46
105.00
2.01
0.65
0.19
0.47
110.00
1.95
0.66
0.19
0.47
115.00
1.88
0.67
0.20
0.46
120.00
1.82
0.67
0.21
0.46
125.00
1.75
0.67
0.22
0.45
130:00
1.68
0.67
0.23
0.44
135.00
1.61
0.67
0.24
0.43
140.00
1.54
----------------
THE REQUIRED
POND SIZE
---------
_ .4660056
ACRE -FT
THE RAINFALL
DURATION
FOR THE ABOVE.POND
STORAGE=
110 MINUTES
'.
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OAKRIDGE BUSINESS PARK PLAZA
'
Proposed Detention / Water Quality Pond - Stage/Storage
'
LOCATION: Oakridge Business Park Thirty Fifth Filing
PROJECT NO: 137-01
COMPUTATIONS BY: PPK
SUBMITTED BY: NORTH STAR DESIGN, INC.
DATE: 10/15/01
V = 1/3 d ( A + B + sgrt(A'B))
where V = volume between contours, ft3
d = depth between contours, ft
A = surface area of contour
Water Quality Volume Required =
0.068 Acre -Feet
Detention Volume Required =
0.47 Acre -Feet
Total Volume Required =
0.538 Acre -Feet
W QC\�
10 YR WSEL
100 YR WSEL
Overflow e/ev
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detention.xls
Stage
(ft)
Surface
Area
W)
Incremental
Storage
(ac-ft)
Total
Storage
(ac-ft)
72.41
0
73
3961
0.02
0.02
73.37
7964
0.05
0.068
74.00
14780
0.20
0.22
74.08
16098
0.03
0.248
74.69
26098
0.32
0.538
75.00
31255
0.52
0.74
75.12
OAKRIDGE BUSINESS PARK PLAZA
Detention Pond Outlet Sizing
(10 yr event)
LOCATION: Oakridge Business Park Thirty Fifth Filing
PROJECT NO: 137-01
COMPUTATIONS BY: PPK
SUBMITTED BY: North Star Design
DATE: 8/6/01
Submerged Orifice Outlet:
release rate is described by the orifice equation,
Qa = CA sgrt( 2g(h-Eo))
where Qo = orifice outflow (cfs)
Co = orifice discharge coefficient
g = gravitational acceleration = 32.20 ft/s
A, = effective area of the orifice (ft`)
Eo = geometric center elevation of the orifice (ft)
h = water surface elevation (ft)
Pond Outlet
Qo = 0.51 cfs
outlet pipe dia = D = 15.0 in
Invert elev. = 4973.25 ft
Eo = 4973.45 ft
h = 4974.08 ft - WSEL
' Co = 0.62
solve for effective area of orifice using the orifice equation
Ao = 0.129 ft`
18.6 in`
orifice dia. = d = 4.87 in
Check orifice discharge coefficient using Figure 5-21 (Hydraulic Engineering)
d/ D = 0.32
kinematic viscosity, v = 1.22E-05 ftZ/s
Reynolds no. = Red = 4Q/(7cdv) = 1.31E+05
Co = (K in figure) = 0.61 check
Use d = 4.87 in
A. = 0.129 ff.` = 18.63 in `
r Qmax = 0.51 cfs
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0AKRIDGE BUSINESS PARK PLAZA
Detention Pond Outlet Sizing
'
(100 yr event)
LOCATION: Oakridge Business Park Thirty Fifth Filing
PROJECT NO: 137-01
COMPUTATIONS BY: PPK
SUBMITTED BY: North Star Design
'
DATE: 8/6/01
Submerged Orifice Outlet:
release rate is described by the orifice equation,
Qo = Cok sgrt( 2g(h-Eo))
where Q. = orifice outflow (cfs)
Co = orifice discharge coefficient
g = gravitational acceleration = 32.20 ft/s
Ao = effective area of the orifice (ft`)
Eo = geometric center elevation of the orifice (ft)
h = water surface elevation (ft)
Pond 1 Outlet
Qo = 1.28 cfs
outlet pipe dia = D = 15.0 in
Invert elev. = 4972.36 ft
Eo = 4972.61 ft
h = 4974.69 ft - WSEL
'
Co = 0.64
solve for effective area of orifice using the orifice equation
Ao = 0.173 ft`
24.9 in`
orifice dia. = d = 5.63 in
Check orifice discharge coefficient using Figure 5-21 (Hydraulic Engineering)
d/ D = 0.38
kinematic viscosity, v = 1.22E-05 ftZ/s
Reynolds no. = Red = 4Q/(ndv) = 2.85E+05
Co = (K in figure) = 0.64 check
Use d = 5.6 in
A, = 0.171 ft' = 24.63 in
Qmax = 1.27 cfs
detention.xls
f
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OAKRIDGE BUSINESS PARK PLAZA
Emergency Overflow Spillway Sizing
LOCATION: Oakridge Business Park Thirty Fifth Filing
PROJECT NO: 137-01
COMPUTATIONS BY: PPK
SUBMITTED BY: North Star Design
DATE: 8/6/01
Equation for flow over weir top Of IenT
Q = CLH312 'Q H
where C = weir coefficient = 3.1 spill elevation
H =overflow height ~— �
L = length of the weir 100 Yr WSEL
Spillway will be designed with max 0.5 ft flow depth, H = 0.41 ft
Size the spillway assuming that the pond outlet is completely clogged.
Pond 2
Q (100) = 17.4 cfs
Spill elev =
4975.12
ft
Min top of berm elev.=
4975.62
Weir length required:
L=
21
ft
Use L =
24
ft
v =
1.62
ft/s
detentionAs
100 yr WSEL = 4974.69 ft
Detention Pond Outlet Pipe
Worksheet for Circular Channel
Project Description
Project File
\\nstar\projects\137-01 egg & i\drainage\oakpark.fm2
Worksheet
Detention Outlet
Flow Element
Circular Channel
Method
Manning's Formula
Solve For
Channel Depth
Input Data
Mannings Coefficient 0.013
'
Channel Slope
0.50 %
Diameter
15.00 in
'
Discharge
1.28 cfs
Results
Depth
0.45 ft
Flow Area
0.40 ft2
Wetted Perimeter
1.61 ft
Top Width
1.20 ft
Critical Depth
0.45 ft
Percent Full
Critical Slope
36,21
0.005256 ft/ft
Velocity
3.19' ft/s
Velocity Head
0.16 ft
'
Specific Energy
0.61 ft
Froude Number
0.97
Maximum Discharge 4.91 cfs
'
Full Flow Capacity
4.57 cfs
Full Flow Slope
0.000393 ft/ft
Flow is subcritical.
08/0
6/01 - RowMaster v5.15
08:38:13 PM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 Page 1 of 1
1 -
Concrete Channel for Det Pond Release
' Worksheet for Rectangular Channel
Project Description
Project File
\\nstar\projects\137-01 egg & i\drainage\oakpark.fm2
Worksheet
Concrete Channel
Flow Element
Rectangular Channel
Method
Manning's Formula
Solve For
Channel Depth
Input Data
Mannings Coefficient 0.013
Channel Slope
0.50 %
Bottom Width
2.00 ft
'
Discharge
1.28 cfs
Results
Depth
0.24 ft
Flow Area
0.48 ft'
Wetted Perimeter
2.48 ft
r
Top Width
2.00 ft
Critical Depth
0.23 ft
Critical Slope
Velocity
0.005290 ft/ft
2.69 ft/s
Velocity Head
0.11 ft
Specific Energy
0,35 ft
'
Froude Number
0.97
Flow is subcritical.
I
u
08/06/01 FlowMaster v5.15
08:38:03 PM Haestad Methods, Inc. 37 Brookside Road Waterbury, CT 06708 (203) 755-1666 Page 1 of 1
8/6/01
LOCATION: Oakridge Business Park Thirty Fifth Filing
ITEM: Water Quality Pond Sizing
COMPUTATIONS BY: ppk
SUBMITTED BY: North Star Design, Inc
From Urban Strom Drainage Criterial Manual, March 1969
(Referenced figures are attached in Appendix F)
Use 40-hour brim -full volume drain time for extended detention basin
Water Quality Capture Volume = WQCV = (required storage/12)'(tributary drainage area)
MAJOR
BASIN
Trib.
area
(ac)
% Imperv.
Req. Storage
(In. of runoff)
from Fig. 5.1
WQCV
(ac-ft)
Dwo
(ft)
req. vol
WQCV •1.2
(ac-ft)
req. arealrow
(int/row)
from Fig. 5-3
POND #1
2.84
60.0
0.24
0.057
1.00
0.068
0.46
WO outlet sizing for pond 1
From Figure 5,
for 3/4 in. hole diameter
Area of hole = 0.44
in'
# of columns = 1
Area provided/row = 0.44
in
Area Required/row = 0.46
in
Use f columns of 3/4" diam holes
e
WQVOL.xls
APPENDIX D
EROSION CONTROL CALCULATIONS
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North Star Design
700 Automation Drive, Unit I
Windsor, CO 80550
EFFECTIVENESS CALCULATIONS
PROJECT:
OAKRIDGE BUSINESS PARK, THIRTY-FIFTH FILING
STANDARD FORM B
COMPLETED BY:
PPK
DATE: 13-Apr-01
EROSION CONTROL
C-FACTOR
P-FACTOR
METHOD
VALUE
VALUE
COMMENT
BARE SOIL
1.00
1.00
SMOOTH CONDITION
ROUGHENED GROUND
1.00
0.90
ROADSAVALKS/BLDG
0.01
1.00
GRAVEL FILTERS
1.00
0.80
PLACED AT OUTLET
SILT FENCE
1.00
0.50
STRAW MULCH
0.06
1.00
ESTABLISHED GRASS
0.08
1.00
FROM FIGURE 8-A
STRAW BARRIERS
1.00
0.80
EFF = (I-C•P)• 100
MAJOR
SUB
BASIN AREA
EROSION CONTROL METHODS
BASIN
BASIN
(Ac)
1
2.81
ROADS/WALKSBLDG
1.93 Ac.
ROUGHENED GR.
0.00 Ac.
GRAVEL FILTER
0.88
STRAW BARRIER
0.00 Ac.
NET C-FACTOR
0.32
NET P-FACTOR
0.84
EFF = (1-C' P)• 100 =
73.0%
0-1
0.14
ROADS/WALKSBLDG
0.00 Ac.
ESTABLISHED GRASS
0.07 Ac.
ROUGHENED GR.
0.00 Ac.
SILT FENCE
0.07 Ac.
STRAWIMULCH
0.00 Ac.
NET C-FACTOR
0.54
NET P-FACTOR
0.75
EFF = (1-C' P)' 100 =
59.5%
0-2
0.20
ROADS/WALKS/BLDG
0.02 Ac.
ROUGHENED GR.
0.00 Ac.
STRAW/MULCH
0.00 Ac.
SILT FENCE
0.18
STRAW BARRIER
0.00
NET C-FACTOR
0.90
NET P-FACTOR
0.55
EFF = (I-C•P)• 100 =
50.4%
TOTAL AREA = 3.15 ac
TOTAL EFF = 71.0% _ (94.0%•29.77 ac. +,. +99.6%'0.40 ac)/1.14 ac
REQUIRED PS = 79.4%
Since 71.0% < 79.4%, the proposed plan does not meet the performance standard
Erosion.xls
1of1
North Star Design, Inc.
700 Automation Drive, Unit I
Windsor, CO 80550
CONSTRUCTION SEQUENCE
STANDARD FORM C
PROJECT: OAKRIDGE BUSINESS PARK, THIRTY-FIFTH FILING
SEQUENCE FOR 2001 ONLY COMPLETED BY: PPK DATE: 06-Aug-01
Indicate by use of a bar line or symbols when erosion control measures will be installed. Major modifications to an
approved schedule may require submitting a new. schedule for approval by the City Engineer.
2001
2002
MONTH
J
A
S
O
N
D
J
F
M
A
M
Demolition
Grading
Wind Erosion Control:
Soil Roughing
Perimeter Barrier
Additional Barriers
Vegetative Methods
Soil Sealant
Other
Rainfall Erosion Control
Structural:
Sediment Trap/Basin
Inlet Filters
Straw Barriers
Silt Fence Barriers
Sand Bags
Bare Soil Preparation
Contour Furrows
Terracing
Asphalt/Concrete Paving
Other
Vegetative:
Permanent Seed Planting
Mulching/Sealant
Temporary Seed Planting
Sod Installation
N ettings/Mats/Blankets
Other
BUILDING CONSTRUCTION
STRUCTURES: INSTALLED BY: CONTRACTOR MAINTAINED BY: DEVELOPER
VEGETATION/MULCHING CONTRACTOR: TO BE DETERMINED BY BID
DATE SUBMITTED: APPROVED BY CITY OF FORT COLLINS ON:
Page 1
APPENDIX E
EXCERPTS FROM PREVIOUS REPORTS
E
MASTER DRAINAGE REPORT
FOR THE
O A R R I D G E B U S I N E 8 8 P A R R
FORT COLLINS, COLORADO
September 24, 1990
PREPARED FOR:
EVERITT COMPANIES
3000 SOUTH COLLEGE AVENUE
FORT COLLINS, COLORADO 80525
PREPARED BY:.
RBD, INC. ENGINEERING CONSULTANTS
2900 SOUTH COLLEGE AVENUE
FORT COLLINS, COLORADO 80525
100 YEAR 10 YEAR
BASIN # CONTROL CONTROL REMARKS
340 YES NONE
330 NO If Possible, if onsite problems exist
320 NO if Cemetary
310 YES it Offsite from north of Harmony
I_ 300 YES of Offsite from west to Lemay
290 YES of Existing
280 NO of Street
270. YES Is
1 260 YES
250 YES " Existing
240 NO Downstream street capacity is OK
I230 YES "
' 220 YES
210 NO " From sump in Innovation to channel
200 NO " Possible YES*; Direct to Pond
I, 160 NO " Internal street system73
120 NO " Possible YES*; Includes Comlinear
110 NO " Internal street system14
I' The 10 year storm model did not include an site specific
detention for the Oakridae site. The above results indicate that control at Pond 1 is adequate to bring the 10 year release rate
below the allowable 0.2 cfs per acre discharge. This includes
offsite Basin 300.
* There may be a need for local detention due to certain physical
site constraints. As an example there may be flat topography that
restricts longitudinal street grade.
2.2.2 Flow Characteristics
' STREET SYSTEM FLOW .DEPTH
' Page 8 of Appendix A is a sorted list of all the basins and
conveyance elements with their respective flow depths. The
internal street system was evaluated according to allowable flow
' depth. The City of Fort Collins criteria states that15 both
local and collector streets may have an 18" depth of runoff in
the gutter for the major (100 year) storm event and arterial
' streets .are only allowed a depth of 0.5' above the crown. There
are no arterial streets internal to the Oakridge site. For
comparative purposes only, the above mentioned evaluation is
based on the arterial standard.
13 Ridge. West half of Harmony, Wheaton and a small portion of oak
14 East half of Harmony, Innovative, McMurry and about half
' of the easterly portion of Oak Ridge.
15 City of Fort Collins, Op. Cit., Table 4-4, page 4-6.
I
1
,
'
SUBBASIN CONNECTION
'
- SUBBASIN BOUNDARY
300
ROUTING ELEMENT
'
s13 BASIN
DETENTION POND No 0 250 x
10 NODE 1 inch 500 ft.
G SECTION NUMBER
NAAS
'
B113 IS OAKRIDGE DRIVE BETWEEN
WHEATON DRIVE AND MCMURRAY DRIVE.
BASIN 114 IS MCMURRAY DRIVE BETWEEN
OAKRIDGE DRIVE AND HARMONY ROAD.
BASIN 115 IS MCMURRAY DRIVE BETWEEN
OAKRIDGE DRIVE AND INLETS AT ELEMENT 51.
'
BASIN 116 IS INNOVATIVE DRIVE.
BASIN 117 IS MCMURRAY DRIVE BETWEEN
KEENLAND DRIVE AND INLETS AT ELEMENT 51.
APPENDIX F
FIGURES AND TABLES
F
DRAINAGE CRITERIA MANUAL (V. 3)
0.
0.
0.
9-1.1992,
UDFCD
STORMWATER QUALITY MANAGEMENT
i
xten
ed De
entior
Basin
(Dry)
10-Hot
r Drain
time
s
Detentic
n Pon
Js (W(
t)
I
1
-Hour
Drain
Time
0 10 20 30 40 50 60 70 80 90 100
Percent Impervious Area in Tributary Watershed
Source: Urbanos, Guo, Tucker (1989)
Note: Watershed inches of runoff shall apply to the
entire watershed tributary to the BMP Facility.
FIGURE 5-1. WATER QUALITY CAPTURE VOLUME (WQCV)
DRAINAGE CRITERIA MANUAL(V. 3)
STRUCTURAL BMPs
0.6
0 0.4
r7
o.(
0.(
0.
0.02
0
vid es
FA
I,
WQCV = 2.1 acre-foo
A114A
I
SOLUTION: Required Area or
j Fjo,
FANAPA
VA III
A FISFAV4ANVAPAI
PAF
VAN
PA
APJJAII
VAAMI
A
loll
■
AREA
1
V4AA
IPA
F4ANOFAA
IIIloll
0.04 0.06 0.10 0.20 0.40 0.60 1.o 2.0 n.v 0.v
Required Area per Row (in.2 )
Source: Douglas County Storm Drainage and Technical Criteria, 1966.
FIGURE 5-3. WATER QUALITY OUTLET SIZING: DRY EXTENDED DETENTION
BASIN WITH A 40-HOUR DRAIN TIME OF THE CAPTURE VOLUME
Rev. 3-1-1994
UDFCD
No Text
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
i
i
1
1
280 S Closc(I Conduit Flow
Red __ d
K
to, 10' 104 t0' 104
M�n
to, 10' 10' 1o`
Red = N 1 il�•r
tfdv
Figure 5-21 Flow coefficient K and Red/K versus the
Reynolds number for orifices, nozzles,
and venturi meters (20, 23)
------------
/
BUILDING B � ((J///
FF=]8.50
SP�r1wmAYY
1
II jbj- �
l - I\ it 1
/
wh YEAR HMEI
/ .KTe.ee
I
T1 i� I L 2
/ 1
I 1 P
OAKRIDGE DRIVE _
------------
NSTRUCTON PLAIN NOTES
The
STANDARD FROBON CONTROI GO
City of Fort Collins Stormwater Utility erosion central Inspector must be notified at
lease 24 hours prior to any construcDan on this site.
All redfulrad perimeter silt fencing shall be installed prior to any land disturbing activity
(stockpiling, stripping, grading, etc.). All other required a orlon control measures Mall
be installed at the appropriate time in the construction Sequence as IndcaledIn the
approvM project ecaedue, aenstrucllan plane and erosken contra report.
Pre -disturbance will shall be protected and retained wherever possible. Remerol
or disturbance of existing vegetation shall be limited to the area required for immedbte
conanDcllan operations and for the Shortest practical period of time.
All soils exposed during land disturbing activity, (stripping. grading, daily Installation.
Stockpiling, filing, etc.) shall be kept In a roughened Condition by ripping or disking along
land contours u HI mulch, vegetation or other permanent erasion control Is Installed. No
soils in areas outside propel street rights of way Shall remain exposed by land disturbing
activity for more than thirty (30) days before required temporary or permanent erosion
control (e.g. sudImulch, landscaping, etc.) is installed, unless olherMse approved by the
Slormwaler Utility.
The property shall be watered and maintained at all times during Construction activities
as to prevent wind -Caused erosion. All land disturbing activities shall be Immedlately
discontinued when fugitive dust Impacts adjacent properties, as determined by the City of
Fort Collins Engineering Deportment.
All temporary (structural) erasion control measures shall be Inapcted and repaired Or
onstructed as sary after each runoff eveassure In order to continued
performance of their Intended function. All retained sediments, particularly those an
paved roadway surfaces, sholl be removed and disposed of in o manner and location so
as not to cause their relents Into any drainageway.
No sail stockpile shop exceed ten (10) feet in height, All sod stockpiles shop be
protected From sediment transport by surface roughening, watering and perimeter all(
fencing. Any soil stockpile remaining after 30 days Mall be seeded and mulcM1ed.
City Ordinance prodibits the tracking, droppin9. or depositing of Bolls Or any other
materld Onto City streets by or from any vehicle. Any Inadvertent deposited mated
Mall be cleaned immediately by the contractor
bibbibbi
BUILDING A
1 H )FWwgNI.N
AQ
I � /
W
NOTE
IF BOTH BUILDINGS AND THE ENTIRE SITE (PARKING
AREAS, LANDSCAPING ETC.) ARE NOT COMPLETED
DURING INITIAL CONSTRUCTION, AN AMENDED (de NEW)
SEDIMENT / ERGSION CONTROL PLAN "a BE NEEDED
FOR THE SECOND BUILDING AND REMAINING SITE WORK.
DETENTION POND SUMMARY
The
STANDARD FROBON CONTROI GO
City of Fort Collins Stormwater Utility erosion central Inspector must be notified at
lease 24 hours prior to any construcDan on this site.
All redfulrad perimeter silt fencing shall be installed prior to any land disturbing activity
(stockpiling, stripping, grading, etc.). All other required a orlon control measures Mall
be installed at the appropriate time in the construction Sequence as IndcaledIn the
approvM project ecaedue, aenstrucllan plane and erosken contra report.
Pre -disturbance will shall be protected and retained wherever possible. Remerol
or disturbance of existing vegetation shall be limited to the area required for immedbte
conanDcllan operations and for the Shortest practical period of time.
All soils exposed during land disturbing activity, (stripping. grading, daily Installation.
Stockpiling, filing, etc.) shall be kept In a roughened Condition by ripping or disking along
land contours u HI mulch, vegetation or other permanent erasion control Is Installed. No
soils in areas outside propel street rights of way Shall remain exposed by land disturbing
activity for more than thirty (30) days before required temporary or permanent erosion
control (e.g. sudImulch, landscaping, etc.) is installed, unless olherMse approved by the
Slormwaler Utility.
The property shall be watered and maintained at all times during Construction activities
as to prevent wind -Caused erosion. All land disturbing activities shall be Immedlately
discontinued when fugitive dust Impacts adjacent properties, as determined by the City of
Fort Collins Engineering Deportment.
All temporary (structural) erasion control measures shall be Inapcted and repaired Or
onstructed as sary after each runoff eveassure In order to continued
performance of their Intended function. All retained sediments, particularly those an
paved roadway surfaces, sholl be removed and disposed of in o manner and location so
as not to cause their relents Into any drainageway.
No sail stockpile shop exceed ten (10) feet in height, All sod stockpiles shop be
protected From sediment transport by surface roughening, watering and perimeter all(
fencing. Any soil stockpile remaining after 30 days Mall be seeded and mulcM1ed.
City Ordinance prodibits the tracking, droppin9. or depositing of Bolls Or any other
materld Onto City streets by or from any vehicle. Any Inadvertent deposited mated
Mall be cleaned immediately by the contractor
bibbibbi
BUILDING A
1 H )FWwgNI.N
AQ
I � /
W
NOTE
IF BOTH BUILDINGS AND THE ENTIRE SITE (PARKING
AREAS, LANDSCAPING ETC.) ARE NOT COMPLETED
DURING INITIAL CONSTRUCTION, AN AMENDED (de NEW)
SEDIMENT / ERGSION CONTROL PLAN "a BE NEEDED
FOR THE SECOND BUILDING AND REMAINING SITE WORK.
DETENTION POND SUMMARY
DETENTION REWIRED
1 0.47 At FT.
DETENTION %tOMDED
1 0.74 AC.FT.
100 NOR H
1 4974.59
MAX RELEASE RATE
I 1.26 CFS
DRAINAGE SUMMARY TABLE
OESION
PdNT
AREA
DESIG.
AREA
ACRES
CIO
C10D
To (10)
MIN
To (IM
MM
0 (to)
CFS
0 (100)
Cis
1
1
2A4
Puss
OJB
12.4
9.6
5.16
19
01
1 0-1
1 0.21
1 0.10
1 0.13
1 &a
I &a
1 0.10
0.28
02
1 0-2
1 %10
1 O.i2
1 0.27
1 6.6
1 0.8
1 0.10
1 0.25
Y
L
- 30 15 0 W 60
SCALE: 1' 30'
W
1
CONSTRUCTION SEQUENCE
STANDARD FGN C
M V, OAKRO¢ BUSINESS PARR NASA
S MMM FOR trot A 2003 CdgFTED eY: PR-1 DATE 121
IN4M awe yap"hwA4Bmeve,wee oLmH1Ae a newt uposis fix, m ev GO all Majorpb ENGAWmadncotkne is
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Sond bass
Bae AN, P
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w,t,tnm Pl Seea
Pan^p/Sep
rot
Temp ... ry Soso
rp
H `nllnlR
nge/Mn1e/B pnMtle
BwtOlnc COXSTRUCTI
STIIUCnaES MSIAIIED OR CONTRACTOR MAINTAINED BY: DE1fl(PEH
IfRTATIONMULCIVNG cMTRACTBe: $9E➢ERINABO¢BLUl
DATE SUBMITTED: APPROKO uY CITY M FORT COLLINS ON'.
LEGEND
Q1 DESIGN POINT
BASIN CRITERIA
O.BO O. RUNOFF COEFFICIENT
AREA IN ACRES
ROW DIRECTION
BASIN BOUNDARY
EXISTING PIPES
® PROPOSED STORM PIPE
OfNoressitits EROSION BALES
— — — — EXISTING 5' CONTOUR
EASING 1' CONTOUR
PROPOSED 5' CONTOUR
PROPOSED 1' CONTOUR
O� SILT FENCE
O- CONSTRUCTION ENTRANCE
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CALL UTIUTY NOTIFICATION
W
CENTER OF COLORADO
0
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1-800SI922=1987
U
LNL 2-BUSINESS DAYS IN ADVANCE
i
BEFORE YW BIG. GRADE. M EXCAVATE
M
L O
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FOR THE G F MC Of NDERCAWND
z
uAKIN UTUTES
Y
Q
City of Fort Collins, Colorado
Q
C
UTILITY PLAN APPROVAL
el
APPROVED:
GtY LtpTmer
Dote
SHEET
CHECKED BY:
Water At wmtewdw unity
CHECKED BY:.0
Dole
/11
Sushru w Unit
Dow
T
CHECKED BY:
PVXI a Rsreetlon
CaU
4 OF 6
CHECKED BY:
Tnflk Bremer
Date
CHECKED BY:
JOa No.
137-01
pate